The present invention relates generally to suspension systems and, more particularly, to seat suspension systems for human operators positioned in or on moving machines. Such machines may include, for example, trucks, aircraft, earth-moving or mine exploration machinery, boats, off-road vehicles, or automobiles, where such machines subject the human operator to vibration.
The exposure of seated workers to long-term vibration may be detrimental to a worker's health, performance, and safety. In many cases, low frequency vibrations, which are prevalent in heavy vehicles, are a major contributing factor to low back pain, fatigue, and stress for the worker.
Thus, for example, the risk factor associated with back illness, such as low back pain and spinal disorders, is substantial for many heavy equipment operators, such as some truck drivers. Such risk for truck drivers is due, in large measure, to the long-term exposure of the trucks and drivers to irregular road excitations.
Many vehicles include a suspension system. Such a system may include spring and shock absorber assemblies between the vehicle's axles and the frame of the vehicle, as well as springs and a cushion built into the driver's seat. Many of such currently available suspension systems have been designed and tested with the objective of attempting to reduce the vibration transmitted to the operator's seat or to the floor beneath the operator's seat. Many seat suspension designs are based on pressure distribution of the body on the seat and movement of the seat itself, rather than the driver's physical response to road vibrations.
Unfortunately, many of the presently available suspension systems still transfer substantial vibration to the operator, aggravating the health risk to the operator. In addition to providing a health risk, poor suspension systems provide an uncomfortable environment for the operator. Consequently, the operator may become unnecessarily tired and his/her performance in operating the equipment may suffer as a result.